Hydroxycitric acid and capsaicin combination alleviates obesity-induced testicular apoptosis, oxidative stress and inflammation

Recent research in rodents suggests that oxidative stress, inflammation, and apoptosis in the testes caused by high-fat diets (HFD) are a cause of male infertility. To investigate the therapeutic efficacy of the combination of hydroxycitric acid and capsaicin (HCC) against male reproductive disorders, we developed an HFD-induced obese rat model. Rats received HFD supplementation for 21 weeks, which induced obesity. From week 16, HCC (100 mg/kg body weight) was administered to investigate its potential to treat testicular toxicity. According to the results of the current study, treatment of obese rats with HCC improved their sperm quality, increased the production of testosterone, follicle-stimulating hormone, and luteinizing hormone and significantly increased the activities of steroidogenic enzymes and corresponding mRNA levels. In addition, HCC decreased lipid peroxidation and nitric oxide levels in both spermatozoa and testes while increasing the expression of mRNA for the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase in the testes, which in turn reduced oxidative stress in the testes. Moreover, after HCC treatment, testicular tissues showed a remarkable decrease in mRNA levels responsible for inflammation (TNF-α, IL-6, NF-κB) and apoptosis (Bax and Bcl-2). Our results suggest that HCC may alleviate obesity-induced male reproductive dysfunction by attenuating oxidative stress, inflammation, and apoptosis in the testes of HFD-induced obese male rats.

Increased serum leptin levels are associated with metabolic syndrome and semen parameters in patients with infertility

This study aims to ascertain the associations between serum leptin levels and metabolic syndrome and semen parameters in patients with infertility. A total of 200 patients who were diagnosed as primary infertility in our hospital were enrolled in this study, and they were divided into MetS group and non-MetS group. About 30 healthy men were enrolled as the control group. The general information, blood lipids, reproductive hormones and semen parameters were collected. We used the Student t test, the Chi-square test, the Kruskal-Wallis test, and the spearman correlation analysis to analyze their relationships. BMI, glucose, TG, follicle-stimulating hormone (FSH), and leptin were significantly higher in MetS infertile patients (P < .001; P < .005; P < .001; P < .001; and P < .001, respectively). While T and high-density lipoprotein (HDL) were significantly lower in MetS infertile patients (P < .01, and P < .001, respectively). Leptin was correlated with sperm progressive motility (R = -0.312, P < .01), and normal morphology (R = -0.458, P < .001). Moreover, sperm concentration was correlated with FSH (R = -0.268, P < .001) and inhibin B (R = 0.401, P < .001), and normal morphology was correlated with HDL (R = 0.233, P < .001) and TG (R = -0.182, P < .01). In primary infertile patients, sperm normal morphology were found to be depressed and related to MetS. Leptin was increased in patients diagnosed with MetS and associated with semen parameters.

Metabolomic signature of sperm in men with obesity-associated asthenozoospermia

PURPOSE

Obese men have a significantly increased risk of developing asthenozoospermia. Sperm motility is directly related to cellular energy supply and metabolic status. Sperm metabolomics research based on Gas chromatography-mass spectrometry (GC-MS) technology can provide useful information for the pathological mechanism, diagnosis, and treatment of obesity-associated asthenozoospermia.

METHODS

Sperm samples were obtained from a healthy control group (n = 49) and patients with obesity-associated asthenozoospermia (n = 40). After the analysis of sperm samples using GC-MS, various multivariate statistical methods such as principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA), and orthogonal partial least squares-discriminant analysis (OPLS-DA) were conducted.

RESULTS

A total of 56 metabolites were identified in the sperm samples. Among them, 19 differential metabolites were found between the two groups. Metabolites such as glutamic acid, fumaric acid, and cysteine were significantly downregulated in the sperm of patients with obesity-associated asthenozoospermia, while metabolites like palmitic acid, stearic acid, and alanine were significantly upregulated. The differential metabolites were enriched in D-glutamine and D-glutamate metabolism; proline, aspartate, and glutamate metabolism; glutathione metabolism and the other metabolic pathways.

CONCLUSION

Obesity may influence the composition of metabolic products in sperm, and metabolomic analysis proves beneficial for the future diagnosis and treatment of obesity-associated asthenozoospermia.

Effect of body mass index on semen quality, sperm chromatin integrity and sperm DNA methylation

Obesity represents a growing problem due to its impacts on human health and reproduction. In this study, we analysed semen quality, sperm DNA integrity and gene-specific CpG methylation in 116 healthy men from normal population. The men were divided into three groups according to their body mass index (BMI), and their ejaculates were analysed using standard methods, sperm chromatin structure assay (SCSA), methylation next generation sequencing (NGS) and amplicon sequencing. The sperm methylation NGS revealed six significantly differentially methylated regions (DMRs). Using subsequent targeted amplicon sequencing in 116 men, two of the DMRs were proved as differentially methylated in sperm of men with normal BMI vs. BMI ≥ 25. The DMRs were located in the EPHA8 and ANKRD11 gene. Also, we detected a significant decline in the EPHA8, ANKRD11 and CFAP46 gene methylation in association with increasing BMI values. The genes EPHA8 and ANKRD11 are involved in the nervous system and brain development; the CFAP46 gene plays a role in a flagellar assembly and is associated with sperm motility. Significantly lower rates of motile and progressive motile sperm were observed in men with BMI ≥ 30. Our results show that excess body weight can modify CpG methylation of specific genes, affect sperm motility, and compromise sperm chromatin integrity. These factors can stand behind the observed reduced fertility in men with obesity. The methylation changes might be transmitted to their offspring through sperm, and become a basis for possible developmental and reproductive issues in the next generation.

Vitamin B12 Is Associated with Higher Serum Testosterone Concentrations and Improved Androgenic Profiles Among Men with Infertility

BACKGROUND

Infertility impacts 16% of North American couples, with male factor infertility contributing to ∼30% of cases. Reproductive hormones, especially testosterone, are essential for spermatogenesis. An age-independent population-level decline in testosterone concentrations over the past few decades has been proposed to be a consequence of diet and lifestyle changes. Vitamin B12 is present in the testes and has been suggested as an adjuvant nutritional therapy for male infertility due to its potential to improve sperm parameters. However, evidence examining the relationship between vitamin B12 and reproductive hormones is limited.

OBJECTIVES

The objective was to cross-sectionally examine the relationship between serum vitamin B12 and male reproductive hormones (luteinizing hormone, follicular stimulating hormone, total testosterone, estradiol, and prolactin).

METHODS

Men with infertility (n = 303) were recruited from Mount Sinai Hospital in Toronto, Canada. Serum was analyzed for vitamin B12 and reproductive hormones. Statistical analyses included nonparametric Spearman's rank correlation coefficient, linear regression, logistic regression, and effect modification by age and BMI linear regressions.

RESULTS

An independent monotonic relationship between serum vitamin B12 and total testosterone (ρ = 0.19, P = 0.001) was observed. Serum vitamin B12 was linearly associated with total testosterone (unadjusted β = 0.0007, P = 0.008 and adjusted β = 0.0005, P = 0.03). Compared to individuals in the lowest tertile of serum vitamin B12, those in the middle tertile (adjusted odds ratio [OR] = 0.48; 95% confidence interval [CI]: 0.25, 0.93, P = 0.03) and the highest tertile (unadjusted OR = 0.41; 95% CI: 0.22, 0.77, P = 0.005 and adjusted OR = 0.44; 95% CI: 0.22, 0.87, P = 0.02) had reduced odds of testosterone deficiency.

CONCLUSIONS

These findings suggest that among men with infertility, low serum vitamin B12 is associated with a higher risk of testosterone deficiency and impaired androgenic hormonal profiles that impact spermatogenesis and consequently, fertility.

Association Between Type 2 Diabetes and Hypogonadism in India: An Observational Study

Introduction

Hypogonadism is a common comorbidity associated with several metabolic disorders including type 2 diabetes (T2D) that can remain undetected without proper screening. Here, we evaluated the prevalence of hypogonadism in Indian male patients with T2D with or without obesity.

Methods

In this prospective, observational study, male patients with T2D and hypogonadism were evaluated symptomatically using the androgen deficiency in ageing male (ADAM) questionnaire at baseline and confirmed on the basis of total testosterone (TT) levels (<300 ng/dL) at Days 5-7 (Visit 2) and 9-14 (Visit 4) assessed after 12 hours of fasting between 8 AM and 10 AM. Prevalence of hypogonadism was presented as proportion of patients.

Results

Of 598 enrolled patients, 526 completed the study. Mean (standard deviation [SD]) age was 50.4 (9.12) years. The percentage of patients with TT <300 ng/dL at visit 2 was 18.4%, while upon repeat confirmation, it reduced to 8.6%. Thus, the prevalence of true hypogonadism was 8.6%. Prevalence of hypogonadism in patients with BMI range of >30 kg/m2 (obese) was 11.1%. At screening, 81.4% (487 of 598) patients had positive ADAM questionnaire results.

Conclusions

Prevalence of hypogonadism in Indian patients with T2D was found to be 8.6% upon repeat evaluation of testosterone. Symptomatic (ADAM questionnaire) as well as biochemical (total testosterone levels with repeat evaluation) confirmation is vital in the definite diagnosis of male hypogonadism.

A comprehensive review on potential role of selenium, selenoproteins and selenium nanoparticles in male fertility

Selenium (Se), a component of selenoproteins and selenocompounds in the human body, is crucial for the development of male reproductive organs, DNA synthesis, thyroid hormone, metabolism, and defence against infections and oxidative damage. In the testis, it must exceed a desirable level since either a shortage or an overabundance causes aberrant growth. The antioxidant properties of selenium are essential for preserving human reproductive health. Selenoproteins, which have important structural and enzymatic properties, control the biological activities of Se primarily. These proteins specifically have a role in metabolism and a variety of cellular processes, such as the control of selenium transport, thyroid hormone metabolism, immunity, and redox balance. Selenium nanoparticles (SeNPs) are less hazardous than selenium-based inorganic and organic materials. Upon being functionalized with active targeting ligands, they are both biocompatible and capable of efficiently delivering combinations of payloads to particular cells. In this review, we discuss briefly the chemistry, structure and functions of selenium and milestones of selenium and selenoproteins. Next we discuss the various factors influences male infertility, biological functions of selenium and selenoproteins, and role of selenium and selenoproteins in spermatogenesis and male fertility. Furthermore, we discuss the molecular mechanism of selenium transport and protective effects of selenium on oxidative stress, apoptosis and inflammation. We also highlight critical contribution of selenium nanoparticles on male fertility and spermatogenesis. Finally ends with conclusion and future perspectives.

Signatures of metabolic diseases on spermatogenesis and testicular metabolism

Diets leading to caloric overload are linked to metabolic disorders and reproductive function impairment. Metabolic and hormonal abnormalities stand out as defining features of metabolic disorders, and substantially affect the functionality of the testis. Metabolic disorders induce testicular metabolic dysfunction, chronic inflammation and oxidative stress. The disruption of gastrointestinal, pancreatic, adipose tissue and testicular hormonal regulation induced by metabolic disorders can also contribute to a state of compromised fertility. In this Review, we will delve into the effects of high-fat diets and metabolic disorders on testicular metabolism and spermatogenesis, which are crucial elements for male reproductive function. Moreover, metabolic disorders have been shown to influence the epigenome of male gametes and might have a potential role in transmitting phenotype traits across generations. However, the existing evidence strongly underscores the unmet need to understand the mechanisms responsible for transgenerational paternal inheritance of male reproductive function impairment related to metabolic disorders. This knowledge could be useful for developing targeted interventions to prevent, counteract, and most of all break the perpetuation chain of male reproductive dysfunction associated with metabolic disorders across generations.

Influence of BMI, Cigarette Smoking and Cryopreservation on Tyrosine Phosphorylation during Sperm Capacitation

Capacitation involves tyrosine phosphorylation (TP) as a key marker. Lifestyle-related factors, such as obesity and smoking, are recognized for their adverse effects on semen quality and male fertility, yet the underlying mechanisms, including their potential impact on TP, remain unclear. Moreover, the effect of sperm cryopreservation on TP at the human sperm population level is unexplored. Flow cytometry analysis of global TP was performed on pre-capacitated, post-capacitated and 1- and 3-hours' incubated fresh and frozen-thawed samples from sperm donors (n = 40). Neither being overweight nor smoking (or both) significantly affected the percentage of sperm showing TP. However, elevated BMI and smoking intensity correlated with heightened basal TP levels (r = 0.226, p = 0.003) and heightened increase in TP after 3 h of incubation (r = 0.185, p = 0.017), respectively. Cryopreservation resulted in increased global TP levels after capacitation but not immediately after thawing. Nonetheless, most donors' thawed samples showed increased TP levels before and after capacitation as well as after incubation. Additionally, phosphorylation patterns in fresh and frozen-thawed samples were similar, indicating consistent sample response to capacitation stimuli despite differences in TP levels. Overall, this study sheds light on the potential impacts of lifestyle factors and cryopreservation on the dynamics of global TP levels during capacitation.

Male Infertility: New Developments, Current Challenges, and Future Directions

There have been many significant scientific advances in the diagnostics and treatment modalities in the field of male infertility in recent decades. Examples of these include assisted reproductive technologies, sperm selection techniques for intracytoplasmic sperm injection, surgical procedures for sperm retrieval, and novel tests of sperm function. However, there is certainly a need for new developments in this field. In this review, we discuss advances in the management of male infertility, such as seminal oxidative stress testing, sperm DNA fragmentation testing, genetic and epigenetic tests, genetic manipulations, artificial intelligence, personalized medicine, and telemedicine. The role of the reproductive urologist will continue to expand in future years to address different topzics related to diverse questions and controversies of pathophysiology, diagnosis, and therapy of male infertility, training researchers and physicians in medical and scientific research in reproductive urology/andrology, and further development of andrology as an independent specialty.

Lipid metabolism in crocodilians: A field with promising applications in the field of ecotoxicology

In the last years, lipid physiology has become an important research target for systems biology applied to the field of ecotoxicology. Lipids are not only essential components of biological membranes, but also participate in extra and intracellular signaling processes and as signal transducers and amplifiers of regulatory cascades. Particularly in sauropsids, lipids are the main source of energy for reproduction, growth, and embryonic development. In nature, organisms are exposed to different stressors, such as parasites, diseases and environmental contaminants, which interact with lipid signaling and metabolic pathways, disrupting lipid homeostasis. The system biology approach applied to ecotoxicological studies is crucial to evaluate metabolic regulation under environmental stress produced by xenobiotics. In this review, we cover information of molecular mechanisms that contribute to lipid metabolism homeostasis in sauropsids, specifically in crocodilian species. We focus on the role of lipid metabolism as a powerful source of energy and its importance during oocyte maturation, which has been increasingly recognized in many species, but information is still scarce in crocodiles. Finally, we highlight priorities for future research on the influence of environmental stressors on lipid metabolism, their potential effect on the reproductive system and thus on the offspring, and their implications on crocodilians conservation.

Effect of laparoscopic sleeve gastrectomy on male reproductive function in Chinese men with obesity: a prospective cohort study

BACKGROUND

Obesity is a widely recognized global public health issue, and bariatric surgery has emerged as an effective intervention for alleviating obesity associated health complications. However, the impact of bariatric surgery on male reproductive function remains inconclusive in the literature. The current understanding of the impact of laparoscopic sleeve gastrectomy (LSG) on male reproductive function remains ambiguous, despite its status as the most commonly performed bariatric surgery. This prospective cohort study aimed to investigate the impact of LSG on erectile function and semen quality.

PATIENTS AND METHODS

A total of 34 obese patients were enrolled in this study and underwent LSG. Prior to the operation and at 3, 6, and 12 months postoperation, all participants were required to complete the International Index of Erectile Function-5 (IIEF-5) questionnaire and undergo a nocturnal erectile function test and semen quality analysis.

RESULTS

Within 12 months postoperation, BMI, blood lipids, and insulin resistance showed significant improvement. The IIEF-5 score increased significantly (18.88±5.97 vs. 23.78±3.19, P <0.05), and the frequency and duration of erections significantly improved compared to baseline. Sperm concentration, total motility, survival rate, and sperm morphology parameters exhibited a significant decline at 3 months but demonstrated a significant improvement at 6 and 12 months postoperation. At 12 months, sperm concentration was shown to be correlated with changes in zinc (r=0.25, P =0.033) as well as changes in testosterone (r=0.43, P =0.013).

CONCLUSIONS

LSG has beneficial effects on erectile function, despite a transient decline in semen quality at 3 months postoperatively, followed by a significant improvement at 12 months.

Antioxidant treatment for oligoasthenoteratozoospermia and varicocele: a DBPC trial to evaluate the impact of age and body mass index

Oxidative stress is one of the main mechanisms responsible for male infertility. Various conditions such as varicocele, obesity, advanced age, and lifestyle can lead to an increase in reactive oxygen species, causing an oxidative imbalance in the reproductive environment. Spermatozoa are sensitive to reactive oxygen species and require energy to carry out their main function of fertilizing the egg. Excessive reactive oxygen species can affect sperm metabolism, leading to immobility, impaired acrosome reaction, and cell death, thereby impairing reproductive success. This double-blind randomized study evaluated the effect of supplementation with L-carnitine, acetyl-L-carnitine, vitamins, and other nutrients on semen quality in 104 infertile patients with or without varicocele, while also investigating the impact of factors such as obesity and advanced age on treatment. Sperm concentration significantly increased in the supplemented group compared to the placebo group ( P = 0.0186). Total sperm count also significantly increased in the supplemented group ( P = 0.0117), as did sperm motility ( P = 0.0120). The treatment had a positive effect on patients up to 35 years of age in terms of sperm concentration ( P = 0.0352), while a body mass index (BMI) above 25 kg m -2 had a negative effect on sperm concentration ( P = 0.0110). Results were not showing a net benefit in stratifying patients in accordance with their BMI since sperm quality increase was not affected by this parameter. In conclusion, antioxidant supplementation may be beneficial for infertile patients and has a more positive effect on younger patients with a normal weight.

Decreased Ubiquitination and Acetylation of Histones 3 and 4 Are Associated with Obesity-Induced Disorders of Spermatogenesis in Mice

BACKGROUND

Obesity, a chronic metabolic disorder, is related to cardiovascular diseases, diabetes, cancer, and reproductive disorders. The relationship between obesity and male infertility is now well recognized, but the mechanisms involved are unclear. We aimed to observe the effect of obesity on spermatogenesis and to investigate the role of histone ubiquitination and acetylation modifications in obesity-induced spermatogenesis disorders.

METHODS

Thirty male C57BL/6J mice were randomly divided into two groups. The control group was fed with a general maintenance diet (12% fat), while a high-fat diet (HFD) group was fed with 40% fat for 10 weeks; then, they were mated with normal females. The fertility of male mice was calculated, testicular and sperm morphology were observed, and the expression levels of key genes and the levels of histone acetylation and ubiquitination modification during spermatogenesis were detected.

RESULTS

The number of sperm was decreased, as well as the sperm motility, while the number of sperm with malformations was increased. In the testes, the mRNA and protein expression levels of gonadotropin-regulated testicular RNA helicase (GRTH/DDX25), chromosome region maintenance-1 protein (CRM1), high-mobility group B2 (HMGB2), phosphoglycerate kinase 2 (PGK2), and testicular angiotensin-converting enzyme (tACE) were decreased. Furthermore, obesity led to a decrease in ubiquitinated H2A (ubH2A) and reduced levels of histone H3 acetylation K18 (H3AcK18) and histone H4 acetylation K5, K8, K12, and K16 (H4tetraAck), which disrupted protamine 1 (Prm1) deposition in testis tissue.

CONCLUSION

These results suggest that low levels of histone ubiquitination and acetylation are linked with obesity-induced disorders during spermatogenesis, contributing to a better understanding of obesity-induced damage to male reproduction.

A ripple effect? The impact of obesity on sperm quality and function

Infertility affects approximately 15% of couples trying to conceive. Male-related causes account for roughly 50% of cases, with obesity emerging as a possible significant factor. Obesity, defined as a body mass index of 30.0 or higher, has become a widespread epidemic associated with numerous health issues, including a decrease of fertility. This review discusses the relationship between obesity and male infertility, particularly focusing on sperm quality and function. An overview of the literature suggests that obesity may influence the male reproductive system via disruptions in hormonal profiles, oxidative stress, and inflammation, leading to changes in sperm parameters. Several studies have discussed if obesity causes a decrease in sperm concentration, motility, and normal morphology, so far without a consensus being reached. However, available evidence suggests an impairment of sperm function in obese men, due to an increase in DNA damage and oxidative stress, impaired mitochondrial function and acrosome reaction in response to progesterone. Finally, the relationship between obesity and assisted reproductive technologies outcomes remains debatable, with conflicting evidence regarding the influence on fertilisation, pregnancy, and live birth rates. Therefore, the actual impact of obesity on human spermatozoa still needs to be clarified, due to the multiple factors potentially in play.

Liraglutide improved the reproductive function of obese mice by upregulating the testicular AC3/cAMP/PKA pathway

BACKGROUND

The incidence of male reproductive dysfunction is increasing annually, and many studies have shown that obesity can cause severe harm to male reproductive function. The mechanism of male reproductive dysfunction caused by obesity is unclear, and there is no ideal treatment. Identification of effective therapeutic drugs and elucidation of the molecular mechanism involved in male reproductive health are meaningful. In this study, we investigated the effects of the GLP-1 receptor agonist liraglutide on sex hormones, semen quality, and testicular AC3/cAMP/PKA levels in high-fat-diet-induced obese mice.

METHODS

Obese mice and their lean littermates were treated with liraglutide or saline for 12 weeks. Body weight was measured weekly. Fasting blood glucose (FBG) was measured using a blood glucose test strip. The serum levels of insulin (INS), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), free testosterone (F-TESTO), estradiol (E2), and sex hormone binding globulin (SHBG) were detected using ELISA. The sperm morphology and sperm count were observed after Pap staining. The mRNA and protein expression levels of testicular GLP-1R and AC3 were measured by RT-qPCR and Western blot, respectively. Testicular cAMP levels and PKA activity were detected using ELISA.

RESULTS

Liraglutide treatment can decrease body weight, FBG, INS, HOMA-IR, E2 and SHBG levels; increase LH, FSH, T, and F-TESTO levels; increase sperm count; decrease the sperm abnormality rate; and increase GLP-1R and AC3 expression levels and cAMP levels and PKA activity in testicular tissue.

CONCLUSIONS

Liraglutide can improve the sex hormone levels and semen quality of obese male mice. In addition to its weight loss effect, liraglutide can improve the reproductive function of obese male mice, which may also be related to the upregulation of AC3/cAMP/PKA pathway in the testis. This work lays the groundwork for future clinical studies.

Decreased AdipoR1 signaling and its implications for obesity-induced male infertility

Obesity is among the risk factors for male infertility. Although several mechanisms underlying obesity-induced male subfertility have been reported, the entire mechanism of obesity-induced male infertility still remains unclear. Here, we show that sperm count, sperm motility and sperm fertilizing ability were decreased in male mice fed a high-fat diet and that the expression of the AdipoR1 gene and protein was decreased, and the expression of pro-apoptotic genes and protein increased, in the testis from mice fed a high-fat diet. Moreover, we demonstrate that testes weight, sperm count, sperm motility and sperm fertilizing ability were significantly decreased in AdipoR1 knockout mice compared to those in wild-type mice; furthermore, the phosphorylation of AMPK was decreased, and the expression of pro-apoptotic genes and proteins, caspase-6 activity and pathologically apoptotic seminiferous tubules were increased, in the testis from AdipoR1 knockout mice. Furthermore, study findings show that orally administrated AdipoRon decreased caspase-6 activity and apoptotic seminiferous tubules in the testis, thus ameliorating sperm motility in male mice fed a high-fat diet. This was the first study to demonstrate that decreased AdipoR1/AMPK signaling led to increased caspase-6 activity/increased apoptosis in the testis thus likely accounting for male infertility.

Effects of Korean Versus Western Diets on Reproductive Function in Young Korean Men: A 12-Week Randomized Parallel Clinical Trial

Background

Studies report that diet may have contributed to a 50-60% decrease in human sperm quality over the past few decades. Unhealthy lifestyles affect the structure of spermatozoa, affecting the male reproductive potential. This study aimed to compare the effects of Korean and Western diets on reproductive function in young male Koreans.

Methods

Study participants were provided either the Korean Diet (KD group) or the Western Diet (WD group) for 12 weeks. Semen quality parameters such as volume, motility, cell count, and sex hormone levels were evaluated. Sexual function was assessed using the International Index of Erectile Function and the Male Sexual Health Questionnaire. Efficacy and safety evaluations were conducted at baseline, 8 weeks, and 12 weeks.

Results

The KD group demonstrated a significantly increased sperm motility after 8 weeks relative to baseline but decreased after 12 weeks. In contrast, sperm motility in the WD group significantly decreased after 8 weeks compared with baseline and remained constant after 12 weeks. Statistically, a near-significant difference was observed between groups (p = 0.057). Similarly, free testosterone levels in the KD group increased after 12 weeks compared with baseline, whereas that in the WD group decreased. The free testosterone levels in the KD group were significantly higher than those in the WD group (p = 0.020). There were no statistically significant differences in other sex hormone and sexual function questionnaires between the groups. None of the participants reported any severe side effects, and no significant alterations in clinical diagnostic test values were detected.

Conclusion

The results of the study strongly reveal that KD positively affects sperm motility and male hormone levels in young men, indicating potential benefits for reproductive function.

Decrease in Sperm Parameters in the 21st Century: Obesity, Lifestyle, or Environmental Factors? An Updated Narrative Review

Semen quality represents a compelling factor for fertility, and delineating the normal values has proven difficult. In the last four decades, several authors have reported a noticeable decline in sperm parameters. Also, studies investigating 'time to pregnancy' have shown that fecundity begins to be reduced when sperm numbers decrease below 30 million, even though according to the 6th edition of the WHO manual, the normal value is currently 16 million/mL or 39 million per ejaculate. There exists sufficient data to suggest a decline in sperm counts over time, even though the clear reason for this adverse trend is not well established, but some associations have been hypothesised, such as maternal smoking during pregnancy. Additional potential factors have yet to be fully illustrated but involve poor diet, increased obesity, and exposure to environmental toxins. Moreover, the change in environmental conditions and more common exposure to endocrine-disrupting chemicals (EDCs), such as pesticides and herbicides, as well as bisphenol A, phthalates, polychlorinated biphenyls, and heavy metals, starting from prenatal life and continuing into adulthood, may exhibit probable features explaining the reduction in sperm parameters. Therefore, the main goal of this narrative review is to furnish an overview of the possible effects of exposure to EDCs on testicular function and spermatogenesis and, also, to summarise the evidence regarding a decrease in sperm quality and examine its potential consequences.

Redox Homeostasis and Nrf2-Regulated Mechanisms Are Relevant to Male Infertility

Infertility represents a significant global health challenge, affecting more than 12% of couples worldwide, and most cases of infertility are caused by male factors. Several pathological pathways are implicated in male infertility. The main mechanisms involved are driven by the loss of reduction-oxidation (redox) homeostasis and the resulting oxidative damage as well as the chronic inflammatory process. Increased or severe oxidative stress leads to sperm plasma membrane and DNA oxidative damage, dysregulated RNA processing, and telomere destruction. The signaling pathways of these molecular events are also regulated by Nuclear factor-E2-related factor 2 (Nrf2). The causes of male infertility, the role of oxidative stress in male infertility and the Keap1-Nrf2 antioxidant pathway are reviewed. This review highlights the regulatory role of Nrf2 in the balance between oxidants and antioxidants as relevant mechanisms to male fertility. Nrf2 is involved in the regulation of spermatogenesis and sperm quality. Establishing a link between Nrf2 signaling pathways and the regulation of male fertility provides the basis for molecular modulation of inflammatory processes, reactive oxygen species generation, and the antioxidant molecular network, including the Nrf2-regulated antioxidant response, to improve male reproductive outcomes.

Biomarkers of Iron Are Associated with Anterior-Pituitary-Produced Reproductive Hormones in Men with Infertility

Approximately 16% of North American couples are affected by infertility, with 30% of cases being attributable to male factor infertility. The regulation of reproductive hormones via the hypothalamic-pituitary-gonadal axis is important for spermatogenesis and subsequently male fertility. Maintaining iron homeostasis is critical to normal reproductive physiological function. This cross-sectional study's objective was to determine the association between serum biomarkers of iron and reproductive hormones. Men experiencing infertility (n = 303) were recruited from Mount Sinai Hospital, Toronto. Serum was analyzed for iron and ferritin as biomarkers of iron status and reproductive hormones (follicle-stimulating hormone, luteinizing hormone, testosterone, estradiol, and prolactin), which were the primary outcome. Associations were determined using non-parametric Spearman's rank correlation coefficient, linear regressions, and logistic regressions. A significant independent monotonic inverse relationship between serum iron and prolactin (p = 0.0002) was found. In linear regression analyses, iron was inversely associated with luteinizing hormone (unadjusted p = 0.03, adjusted p = 0.03) and prolactin (unadjusted p = 0.001 and adjusted p = 0.003). Serum ferritin was inversely associated with both gonadotropins, follicle-stimulating hormone (adjusted p = 0.03), and luteinizing hormone (adjusted p = 0.02). These findings suggest that biomarkers of iron are associated with pituitary-produced reproductive hormones, which play a role in the hypothalamic-pituitary-gonadal signaling pathway involved in spermatogenesis, testicular testosterone production, and male fertility.

Role of Mediterranean diet in endocrine diseases: a joint overview by the endocrinologist and the nutritionist

PURPOSE

The purpose of this review is to examine the current evidence on the potential role of Mediterranean diet (MD) in the prevention and management of endocrine disorders and to highlight the importance of interdisciplinary collaboration between endocrinologists and nutritionists.

METHODS

A literature search was conducted using PubMed and Google Scholar databases to identify relevant studies published in English. Studies were selected based on their relevance to the role of MD in the prevention and management of endocrine disorders. The search terms included "Mediterranean diet," "endocrine disorders," "thyroid disorders," "gonadal disorders," and "neuroendocrine tumors".

RESULTS

The studies reviewed suggest that MD may have a beneficial effect in the prevention and management of various endocrine disorders, including thyroid disorders, gonadal disorders, and neuroendocrine tumors. MD has been associated with decreased risk of nodular thyroid disease and thyroid cancer, improved male and female reproductive health, and a potential role in the management of neuroendocrine tumors. MD's anti-inflammatory and antioxidant properties, as well as its high levels of phytochemicals, may play a role in its beneficial effects.

CONCLUSION

Interdisciplinary collaboration between endocrinologists and nutritionists is essential for the optimal management of endocrine disorders, including the potential role of MD in their prevention and management. While further research is needed, the current evidence suggests that MD may have a protective effect against endocrine disorders, and its incorporation into dietary recommendations may be beneficial.

The Molecular Basis of Male Infertility in Obesity: A Literature Review

The rising incidence of obesity has coincided with rising levels of poor reproductive outcomes. The molecular basis for the association of infertility in obese males is now being explained through various mechanisms. Insulin resistance, hyperglycemia, and changes in serum and gonadal concentrations of adipokines, like leptin, adiponectin, resistin, and ghrelin have been implicated as causes of male infertility in obese males. The effects of obesity and hypogonadism form a vicious cycle whereby dysregulation of the hypothalamic-pituitary-testicular axis-due to the effect of the release of multiple mediators, thus decreasing GnRH release from the hypothalamus-causes decreases in LH and FSH levels. This leads to lower levels of testosterone, which further increases adiposity because of increased lipogenesis. Cytokines such as TNF-α and interleukins, sirtuins, and other inflammatory mediators like reactive oxygen species are known to affect fertility in obese male adults. There is evidence that parental obesity can be transferred through subsequent generations to offspring through epigenetic marks. Thus, negative expressions like obesity and infertility have been linked to epigenetic marks being altered in previous generations. The interesting aspect is that these epigenetic expressions can be reverted by removing the triggering factors. These positive modifications are also transmitted to subsequent generations.

[Male infertility, environment and lifestyle]

BACKGROUND

Since the 1970s, there has been a quantitative and qualitative decline in sperm parameters. The main hypothesis to explain such a rapid evolution is the involvement of environmental and behavioral phenomena.

METHODS

A bibliographic search limited to English and French literature in men published before 7/2023 was carried out on the links between fertility and pollution, xenobiotics, tobacco, narcotics, cannabis, alcohol, weight, sport, sedentary lifestyle, sleep and anabolics.

RESULTS

Profound changes in lifestyle have occurred over the past 50 years: reduced sleep time, sedentary lifestyle, dietary changes, tobacco consumption, use of narcotics and anabolics. These changes have a proven impact on spermogram parameters, and should be corrected in an effort to optimize reproductive health. Other environmental parameters: pollution, exposure to heavy metals, exposure to xenobiotics, phthalates and pesticides… will be more difficult to exclude from patients' daily lives, but deserve to be taken more into account.

CONCLUSION

This review should help the urologist to assess and counsel patients in order to improve their reproductive health. These factors should be routinely investigated in infertile men.

Metabolomics profiling of seminal plasma in obesity-induced asthenozoospermia

BACKGROUND

Asthenozoospermia is one of the essential causes of male infertility, and its incidence is significantly higher in obese men. Due to its complex etiology and unknown pathomechanism, the diagnosis and treatment of obesity-induced asthenozoospermia is a prevalent problem in reproductive medicine.

OBJECTIVE

This study aims to explore major differential metabolites and metabolic pathways in seminal plasma and pathological mechanisms for obesity-induced asthenozoospermia.

MATERIALS AND METHODS

We performed non-target metabolomic studies on the seminal plasma of healthy men with normal semen parameters (HN group, n = 20), obese men with normal semen parameters (ON group, n = 20), and men with obesity-induced asthenozoospermia (OA group, n = 20) based on gas chromatography-mass spectrometry. Metabolic profilings and related pathway analyses were conducted to discriminate differential metabolites and metabolic pathways.

RESULTS

A total of 20 differential metabolites including fructose, succinic acid, aconitic acid, methylmaleic acid, glucopyranose, serine, valine, leucine, phenylalanine, glycine, glutamic acid, alanine, proline and threonine were identified in HN group and ON group; 24 differential metabolites including glucose, fructose, pyruvic acid, citric acid, succinic acid, aconitic acid, glucopyranose, glutamic acid, valine, leucine, glycine, phenylalanine, lysine, citrulline, proline and alanine were produced in OA group and ON group; and 28 differential metabolites including glucose, fructose, citric acid, succinic acid, glucopyranose, valine, glycine, serine, leucine, phenylalanine, alanine, threonine, proline, glutamic acid, citrulline, lysine and tyrosine were produced in OA group and HN group. In addition, abnormal energy metabolism including carbohydrate metabolism (TCA cycle, glycolysis/gluconeogenesis, and pyruvate metabolism) and amino acid metabolism (phenylalanine, tyrosine, and tryptophan biosynthesis, D-glutamine and D-glutamate metabolism; phenylalanine metabolism, etc.) were found in ON group and OA group.

CONCLUSION

Obesity could affect the metabolite composition in seminal plasma and abnormal energy metabolism in seminal plasma mainly including carbohydrate metabolism and amino acid metabolism were closely related to obesity-induced asthenozoospermia.

Obesity is associated with quality of sperm parameters in men with infertility: a cross-sectional study

BACKGROUND

Previous studies examined the effects of obesity on sperm parameters and reported inconsistent results. Thus, the present study aimed to evaluate the association between obesity and the quality of sperm parameters in infertile men.

MATERIAL AND METHODS

The present cross-sectional study evaluated 218 infertile men aged 20-50. To this end, the 168-item food frequency questionnaire (FFQ) was utilized to evaluate dietary intake. The anthropometric and biochemical variables were examined using standard methods. Further, the association between obesity and the quality of sperm parameters was evaluated using the controlled linear regression for potential confounders.

RESULTS

The normal sperm morphology had a significant inverse association with BMI [adjusted β - 0.074, CI (- 0.141 to - 0.008), P = 0.029] and WC [adjusted β - 0.026, CI (- 0.051 to - 0.001), P = 0.038]. Additionally, visceral fat had a marginal inverse association with normal sperm morphology [adjusted β - 0.065, CI (- 0.138 to 0.008), P = 0.079] and non-progressive sperm motility [adjusted β - 0.241, CI (- 0.495 to 0.014), P = 0.063].

CONCLUSION

Even though the present results indicated that obesity, abdominal obesity, and visceral fat had inverse associations with normal sperm morphology, more mechanism-based studies should be conducted to confirm these findings.

Clinical and Therapeutic Implications of Male Obesity

The prevalence of obesity, a disorder linked to numerous comorbidities and metabolic complications, has recently increased dramatically worldwide and is highly prevalent in men, even at a young age. Compared to female patients, men with obesity more frequently have delayed diagnosis, higher severity of obesity, increased mortality rate, and only a minority of obese male patients are successfully treated, including with bariatric surgery. The aim of this review was to present the current state of knowledge about the clinical and therapeutic implications of obesity diagnosed in males.

Ascorbic acid is associated with favourable hormonal profiles among infertile males

Introduction

Infertility affects about 16% of North American couples, with the male factor contributing to ∼30% of cases. Reproductive hormones play an integral role in regulating the reproductive system and consequently, fertility. Oxidative stress reduces testosterone synthesis, and reduction in oxidative stress can improve hormone profiles. Ascorbic acid is a potent antioxidant that accounts for up to 65% of seminal antioxidant activity; however, its effects on reproductive hormones in humans are unknown.

Methods

The objective was to determine the association between serum ascorbic acid concentrations and male reproductive hormones. We conducted a cross-sectional study involving infertile males (n = 302) recruited from Mount Sinai Hospital, Toronto. Serum was analyzed for ascorbic acid, luteinizing hormone (LH), follicular stimulating hormone (FSH), total testosterone (TT), prolactin and estradiol. Statistical analyses included Spearman's rank correlations, linear regressions, logistic regressions, simple slope and Johnson-Neyman procedures.

Results

After adjusting for covariates, ascorbic acid was inversely associated with LH (P = 0.01). Ascorbic acid was positively associated with TT only among males over the age of 41.6 years (P = 0.01).

Discussion

Our findings show that ascorbic acid is associated with higher testosterone levels and improved androgenic status in infertile males, and some of the effects appear to be age dependent.

Correlation between PRDX2 and spermatogenesis under oxidative stress

BACKGROUND

Obesity is one of the world's diseases that endanger human health, causing systemic inflammation caused by excessive reactive oxygen damage. An increase in the proportion of obese people with reduced sperm motility has been reported. But the mechanism behind it remains unclear. Peroxiredoxin 2 (PRDX2) is a member of the peroxidase family that effectively removes hydrogen peroxide. This study is to clarify the expression of PRDX2 in the testes of obese mice and lay a foundation for further exploration of the regulatory and protective effects of PRDX2 on spermatogenesis.

METHOD

A model of high-fat-induced obesity in animals was constructed, and the expression of PRDX2 in the testes of the two groups was detected by immunohistochemistry, western blotting, immunofluorescence and other techniques. Hydrogen peroxide (H₂O₂) and cholesterol were co-cultured in testicular support cells for 48 h to observe the expression of PRDX2.

RESULT

PRDX2 expression was reduced in the testes of the obese group, and immunohistochemistry showed that it was mainly localized to supporting cells. H₂O₂ inhibits the expression of PRDX2 in Sertoli cells, and high cholesterol upregulates the expression of PRDX2 in Sertoli cells.

CONCLUSION

PRDX2 has some antioxidant properties against changes in the testicular environment caused by HFD. And under short-term oxidative stress to enhance its antioxidant capacity. PRDX2 may be involved in maintaining the oxidative balance of the spermatogenesis environment.

Obesity-induced oxidative stress and mitochondrial dysfunction negatively affect sperm quality

Obesity is a systemic metabolic disease that can induce male infertility or subfertility through oxidative stress. The aim of this study was to determine how obesity impairs sperm mitochondrial structural integrity and function, and reduces sperm quality in both overweight/obese men and mice on a high-fat diet (HFD). Mice fed the HFD demonstrated higher body weight and increased abdominal fat content than those fed the control diet. Such effects accompanied the decline in antioxidant enzymes, such as glutathione peroxidase (GPX) and catalase and superoxide dismutase (SOD) in testicular and epidydimal tissues. Moreover, malondialdehyde (MDA) content significantly increased in sera. Mature sperm in HFD mice demonstrated higher oxidative stress, including increased mitochondrial reactive oxygen species (ROS) levels and decreased protein expression of GPX1, which may impair mitochondrial structural integrity and reduce mitochondrial membrane potential (MMP) and ATP production. Moreover, cyclic AMPK phosphorylation status increased, whereas sperm motility declined in the HFD mice. Clinical studies demonstrated that being overweight/obese reduced SOD enzyme activity in the seminal plasma and increased ROS in sperm, accompanied by lower MMP and low-quality sperm. Furthermore, ATP content in the sperm was negatively correlated with increases in the BMI of all clinical subjects. In conclusion, our results suggest that excessive fat intake had similar disruptive effects on sperm mitochondrial structure and function, as well as oxidative stress levels in humans and mice, which in turn induced lower sperm motility. This agreement strengthens the notion that fat-induced increases in ROS and impaired mitochondrial function contribute to male subfertility.

Dietary Sugar Shifts Mitochondrial Metabolism and Small RNA Biogenesis in Sperm

Aims: Increasing concentrations of dietary sugar results in a linear accumulation of triglycerides in male Drosophila, while inducing a U-shaped obesity response in their offspring. Here, using a combination of proteomics and small RNA (sRNA) sequencing, we aimed at understanding the molecular underpinning in sperm for such plasticity. Results: Proteomic analysis of seminal vesicles revealed that increasing concentrations of dietary sugar resulted in a bell-shaped induction of proteins involved in metabolic/redox regulation. Using stains and in vivo redox reporter flies, this pattern could be explained by changes in sperm production of reactive oxygen species (ROS), more exactly mitochondria-derived H₂O₂. By quenching ROS with the antioxidant N-acetyl cysteine and performing sRNA-seq on sperm, we found that sperm miRNA is increased in response to ROS. Moreover, we found sperm mitosRNA to be increased in high-sugar diet conditions (independent of ROS). Reanalyzing our previously published data revealed a similar global upregulation of human sperm mitosRNA in response to a high-sugar diet, suggesting evolutionary conserved mechanisms. Innovation: This work highlights a fast response to dietary sugar in mitochondria-produced H₂O₂ in Drosophila sperm and identifies redox-sensitive miRNA downstream of this event. Conclusions: Our data support a model where changes in the sperm mitochondria in response to dietary sugar are the primary event, and changes in redox homoeostasis are secondary to mitochondrial ROS production. These data provide multiple candidates for paternal intergenerational metabolic responses as well as potential biomarkers for human male fertility.

Effect of Dietetic Obesity on Testicular Transcriptome in Cynomolgus Monkeys

Obesity is a metabolic disorder resulting from behavioral, environmental and heritable causes, and can have a negative impact on male reproduction. There have been few experiments in mice, rats, and rabbits on the effects of obesity on reproduction, which has inhibited the development of better treatments for male subfertility caused by obesity. Nonhuman primates are most similar to human beings in anatomy, physiology, metabolism, and biochemistry and are appropriate subjects for obesity studies. In this investigation, we conducted a transcriptome analysis of the testes of cynomolgus monkeys on high-fat, high-fructose, and cholesterol-rich diets to determine the effect of obesity on gene expression in testes. The results showed that the testes of obese monkeys had abnormal morphology, and their testes transcriptome was significantly different from that of non-obese animals. We identified 507 differentially abundant genes (adjusted p value < 0.01, log2 [FC] > 2) including 163 up-regulated and 344 down-regulated genes. Among the differentially abundant genes were ten regulatory genes, including IRF1, IRF6, HERC5, HERC6, IFIH1, IFIT2, IFIT5, IFI35, RSAD2, and UBQLNL. Gene ontology (GO) and KEGG pathway analysis was conducted, and we found that processes and pathways associated with the blood testes barrier (BTB), immunity, inflammation, and DNA methylation in gametes were preferentially enriched. We also found abnormal expression of genes related to infertility (TDRD5, CLCN2, MORC1, RFX8, SOHLH1, IL2RB, MCIDAS, ZPBP, NFIA, PTPN11, TSC22D3, MAPK6, PLCB1, DCUN1D1, LPIN1, and GATM) and down-regulation of testosterone in monkeys with dietetic obesity. This work not only provides an important reference for research and treatment on male infertility caused by obesity, but also valuable insights into the effects of diet on gene expression in testes.

High-fat diet induced obesity alters Dnmt1 and Dnmt3a levels and global DNA methylation in mouse ovary and testis

Obesity impairs reproductive capacity, and the link between imprinting disorders and obesity has been discussed in many studies. Recent studies indicate that a high-fat diet may cause epigenetic changes in maternal and paternal genes, which may be transmitted to offspring and negatively affect their development. On this basis, our study aims to reveal the changes in DNA methylation and DNA methyltransferase enzymes in the ovaries and testes of C57BL/6 mice fed a high-fat diet and created a model of obesity, by comparing them with the control group. For this purpose, we demonstrated the presence and quantitative differences of DNA methyltransferase 1 and DNA methyltransferase 3a enzymes as well as global DNA methylation in ovaries and testis of C57BL/6 mice fed a high-fat diet by using immunohistochemistry and western blot methods. We found that a high-fat diet induces the levels of Dnmt1 and Dnmt3a proteins (p < 0.05). We observed increased global DNA methylation in testes but, interestingly, decreased global DNA methylation in ovaries. We think that our outcomes have significant value to demonstrate the effects of obesity on ovarian follicle development and testicular spermatogenesis and may bring a new perspective to obesity-induced infertility treatments. Additionally, to the best of our knowledge, this is the first study to document dynamic alteration of Dnmt1 and Dnmt3a as well as global DNA methylation patterns during follicle development in healthy mouse ovaries.

Gut microbiota involved in spermatogenic function of Sancai Lianmei granules in obese mice

Obesity is a well-established cause of reduced fertility and semen quality in men. Current evidence suggests that Sancai Lianmei granules (SCLM) effectively improve sexual function and semen quality in diabetic patients, while the gut microbiota can influence disease metabolism through various mechanisms. However, the effect of SCLM on the obesity-induced decrease in semen quality and on the gut microbiota is unclear. This study aimed to investigate the effects of SCLM on spermatogenic function and gut microbiota in obese mice. Obese mice were induced by a high-fat diet, and lipid metabolism, spermatogenic function, inflammatory factors, oxidative stress, and autophagy were analyzed to determine the effects of SCLM and SCLM-fecal microbiota transplantation (FMT). In addition, changes in the gut microbiota of mice were analyzed. SCLM and SCLM + FMT could effectively reduce the levels of total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL); decrease the expression of oxidative stress products malondialdehyde (MDA) and 8-hydroxyde-oxyguanosine (8-OHdG); and increase sperm density and sperm viability in obese mice while inhibiting the inflammatory responses and excessive cellular autophagy, indicating that SCLM and SCLM + FMT exerted a protective effect on spermatogenic functions. Furthermore, SCLM affected the gut microbiota composition in mice. This study determined that obesity can lead to reduced sperm motility and affect the composition of the gut microbiota, while SCLM can regulate blood lipids in mice directly or indirectly by regulating gut microbiota changes, and may improve sperm motility in obese mice by reducing oxidative stress and autophagy. In addition, FMT enhanced this effect, which may be related to the diversity of gut microbiota.

Antioxidant Intervention against Male Infertility: Time to Design Novel Strategies

Infertility is a highly prevalent condition, affecting 9-20% of couples worldwide. Among the identifiable causes, the male factor stands out in about half of infertile couples, representing a growing problem. Accordingly, there has been a decline in both global fertility rates and sperm counts in recent years. Remarkably, nearly 80% of cases of male infertility (MI) have no clinically identifiable aetiology. Among the mechanisms likely plausible to account for idiopathic cases, oxidative stress (OS) has currently been increasingly recognized as a key factor in MI, through phenomena such as mitochondrial dysfunction, lipid peroxidation, DNA damage and fragmentation and finally, sperm apoptosis. In addition, elevated reactive oxygen species (ROS) levels in semen are associated with worse reproductive outcomes. However, despite an increasing understanding on the role of OS in the pathophysiology of MI, therapeutic interventions based on antioxidants have not yet provided a consistent benefit for MI, and there is currently no clear consensus on the optimal antioxidant constituents or regimen. Therefore, there is currently no applicable antioxidant treatment against this problem. This review presents an approach aimed at designing an antioxidant strategy based on the particular biological properties of sperm and their relationships with OS.

Endoplasmic reticulum stress increases exosome biogenesis and packaging relevant to sperm maturation in response to oxidative stress in obese mice

BACKGROUND

Mammalian sperm maturation in the epididymis is mainly modulated by exosomes that are secreted into the epididymal lumen from epididymal epithelial cells (EECs). Exposure to oxidative stress (OS) resulting from being fed a high fat diet (HFD) reduces sperm fertility, which is one of the cause inducing male infertility. Thus, we hypothesize that stress-induced changes in exosome content play a critical role in mediating this detrimental process.  METHODS: An obese mouse model was established by feeding a HFD. Then oxidative stress status was measured in the mouse caput epididymis, epididymal fluid and spermatozoa. Meanwhile, epididymis-derived purified exosomes were isolated and validated. Subsequently, liquid chromatography tandem mass spectrometry (LC-MS) was used to perform proteomic analysis of purified exosomes. Gene Ontology (GO) analysis was performed along with pathway enrichment to identify differentially expressed proteins (DEPs).

RESULTS

Two hundred and two DEPs mostly related to endoplasmic reticulum (ER) function were identified in the exosomes separated from the epididymis of control mice and obese mice. The ER stress and CD63 (an exosome marker), both increased in the caput epididymis of obese mice. Furthermore, an in vitro study showed that palmitic acid (PA), an-oxidative stress inducer, increased exosome biogenesis and secretion in the EECs.

CONCLUSION

Oxidative stress in the epididymal microenvironment induces ER stress in the EECs. This effect alters the epididymis-derived exosome content, profile and amounts of their differentially expressed ER proteins. Such changes may affect exosome biogenesis and cargo packaging, finally leading to abnormalities in sperm maturation and fertility.

Enterotypes in asthenospermia patients with obesity

The essence of enterotypes is stratifying the entire human gut microbiome, which modulates the association between diet and disease risk. A study was designed at the Center of Reproductive Medicine, Shengjing Hospital of China Medical University and Jinghua Hospital of Shenyang. Prevotella and Bacteroides were analyzed in 407 samples of stool, including 178 men with enterotype B (61 normal, 117 overweight/obese) and 229 men with enterotype P (74 normal, 155 overweight/obese). The ratio between Prevotella and Bacteroides abundance, P/B, was used as a simplified way to distinguish the predominant enterotype. In enterotype P group (P/B ≥ 0.01), obesity was a risk factor for a reduced rate of forward progressive sperm motility (odds ratio [OR] 3.350; 95% confidence interval [CI] 1.881-5.966; P < 0.001), and a reduced rate of total sperm motility (OR 4.298; 95% CI 2.365-7.809; P < 0.001). Obesity was also an independent risk factor (OR 3.131; 95% CI 1.749-5.607; P < 0.001) after adjusting follicle-stimulating hormone. In enterotype P, body mass index, as a diagnostic indicator of a reduced rate of forward progressive sperm motility and a decreased rate of decreased total sperm motility, had AUC values of 0.627 (P = 0.001) and 0.675 (P < 0.0001), respectively, which were significantly higher than the predicted values in all patients. However, in enterotype B group (P < 0.01), obesity was not a risk factor for asthenospermia, where no significant difference between obesity and sperm quality parameters was observed. This study is tried to introduce enterotypes as a population-based individualized classification index to investigate the correlation between BMI and asthenospermia. In our study, overweight/obese men with enterotype P were found to have poorer sperm quality. however, sperm quality was not associated with overweight/obese in men with enterotype B. Thereof, BMI is a risk factor for asthenospermia only in men with enterotype P, but not in men with enterotype B.

Obesity: A Doorway to a Molecular Path Leading to Infertility

The dramatic rise in obesity has recently made it a global health issue. About 1.9 billion were overweight, and 650 million global populations were obese in 2016. Obese women suffer longer conception time, lowered fertility rates, and greater rates of miscarriage. Obesity alters hormones such as adiponectin and leptin, affecting all levels within the hypothalamic-pituitary-gonadal axis. Advanced glycation end products (AGEs) and monocyte chemotactic protein-1 (MCP-1) are inflammatory cytokines that may play an important role in the pathophysiology of ovarian dysfunction in obesity. In obese males, there are altered sperm parameters, reduced testosterone, increased estradiol, hypogonadism, and epigenetic modifications transmitted to offspring. The focus of this article is on the possible adverse effects on reproductive health resulting from obesity and sheds light on different molecular pathways linking obesity with infertility in both female and male subjects. Electronic databases such as Google Scholar, Embase, Science Direct, PubMed, and Google Search Engine were utilized to find obesity and infertility-related papers. The search strategy is detailed in the method section. Even though multiple research work has shown that obesity impacts fertility in both male and female negatively, it is significant to perform extensive research on the molecular mechanisms that link obesity to infertility. This is to find therapeutics that may be developed aiming at these mechanisms to manage and prevent the negative effects of obesity on the reproductive system.

Effects of Moderate-Intensity Continuous Training and High-Intensity Interval Training on Testicular Oxidative Stress, Apoptosis and m6A Methylation in Obese Male Mice

Exercise is an effective way to improve reproductive function in obese males. Oxidative stress and apoptosis are important pathological factors of obesity-related male infertility. Accumulating studies have demonstrated that N6-methyladenosine (m6A) methylation is associated with obesity and testicular reproductive function. Our study aimed to investigate and compare the effect of 8 weeks of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on testicular oxidative stress, apoptosis and m6A methylation in obese male mice. Male C57BL/6 mice were randomly allocated into the four groups: normal diet (ND) group, high-fat diet (HFD) group, high-fat diet with moderate-intensity continuous training (HFD-MICT) group and high-fat diet with high-intensity interval training (HFD-HIIT) group. Mice in the HFD-MICT and HFD-HIIT groups were subjected to 8 weeks of MICT or HIIT treadmill protocols after 12 weeks of HFD feeding. We found that MICT and HIIT increased the protein expression of Nrf2, HO-1 and NQO-1 in the testes of obese mice, and HIIT increased it more than MICT. The Bax/Bcl-2 ratio, Cleaved Caspase-3 protein expression and TUNEL-positive cells were consistently up-regulated in the testes of obese mice, but MICT and HIIT restrained these HFD-induced effects. In addition, HFDs increased m6A levels and the gene expression of METTL3, YTHDF2 and FTO in the testes, but these effects were reversed by MICT and HIIT. However, HIIT was more effective than MICT in reducing m6A methylation in the testes of obese mice. These results demonstrate that both MICT and HIIT protected against HFD-induced oxidative stress, apoptosis and m6A methylation in testicular tissues; as a result, testicular morphological and functional impairment improved. In particular, HIIT was more beneficial than MICT in increasing the mRNA expression of steroidogenic enzymes and testicular antioxidant capacity and decreasing m6A methylation in the testes of HFD-fed mice.

Akkila S, S. Ibrahim M. Adiponectin and the expression of BAX and caspase 3 in high-fructose - induced testicular injury in albino mice

Introduction and Aim: The increase in the prevalence of obesity and metabolic syndrome in recent decades has been correlated with high consumption of high-fructose and high-fat diets and has been associated with increased rates of male infertility. The aim of this study was to investigate how high fructose diet exerts its effect upon testicular morphology in addition to examine the potential effects of adiponectin treatment in restoring the architecture of seminiferous tubules through the expression of immunohistochemical markers BAX and caspase-3. Materials and Methods: Twenty-five adult albino mice were divided into three groups: In Group 1, mice fed with diet contained high concentration of fructose followed by adiponectin injection, Group 2, the mice fed with high concentration of fructose diet and received a saline placebo injection, and Group 3 (control) was nourished a regular food for 8 weeks. The parameters studied included changes in animal body weight, testicular spermatogenesis index, spermatogonia count, apoptotic index, exfoliative epithelium percentage and immunohistochemical scores for testicular BAX and caspase-3 expression. Results: Animals on high fructose diet showed increase in body weight which was markedly reduced by adiponectin treatment. High fructose diet also resulted in reduced spermatogenesis index and spermatogonia count with increased apoptotic and epithelial exfoliation indices. High fructose diet was also associated with high-fructose induced obesity and significantly associated with increased BAX and caspase-3 expression alleviated by adiponectin treatment. Conclusion: High-fructose intake induces obesity and obesity-related reduction in male fertility by reducing spermatogenesis and enhancing testicular cell apoptosis via different pathophysiological mechanisms. Such effects and mechanism can be reversed and corrected with adiponectin treatment.

Genipin improves lipid metabolism and sperm parametersin obese mice via regulation of miR-132 expression

Obesity has now surpassed malnutrition and infectious diseases as the most significant contributor to health problems worldwide. In particular, obesity is associated with several metabolic disorders, including hyperlipidemia, hepatic steatosis, and subfertility. Genipin (GNP), the aglycone of geniposide, is isolated from the extract of the traditional Chinese medicine Gardenia jasminoides Ellis and has been used in traditional oriental medicine against several inflammation-driven diseases. However, the effect and molecular mechanism of GNP on obesity-associated dyslipidemia and sperm dysfunction still need to be explored. In this study, we detect the effects of GNP on hyperlipidemia, hepatic lipid accumulation and sperm function using a high-fat diet (HFD)-induced obese mouse model. We find that obese mice treated with GNP show an improvement in body weight, serum triglyceride levels, serum hormone levels, serum inflammatory cytokines, hepatic steatosis and sperm function. At the molecular level, HFD/GNP diversely regulates the expression of miR-132 in a tissue-specific manner. miR-132 further targets and regulates the expression of SREBP-1c in liver cells, as well as the expressions of SREBP-1c and StAR in Leydig cells in the testis, thus modifying lipogenesis and steroidogenesis, respectively. Collectively, our data demonstrate that GNP shows a broad effect on the improvement of HFD-induced metabolic disorder and sperm dysfunction in male mice by tissue-specific regulation of miR-132. Our findings reveal the function GNP in ameliorating hepatic lipid metabolism and sperm function and suggest that this compound is a versatile drug to treat metabolic disorders.

Effects of Cordyceps militaris fermentation products on reproductive development in juvenile male mice

Cordyceps militaris (CM) is a popular medicinal fungus; however, few studies have focused on its impact on the male reproductive system. We evaluated the effects of CM fermentation products on the reproductive development of juvenile male (JM) mice. Mice were divided into four experimental groups, each fed 5% CM products (weight per weight (w/w) in normal diet): extracellular polysaccharides (EPS), fermentation broth (FB), mycelia (MY), and whole fermentation products (FB plus MY, FBMY) for 28 days, while mice in the control group (CT) were fed a normal diet. Basic body parameters, testicular structure, sperm parameters, and sex hormones concentrations were analyzed. Compared to the CT group, mice in the EPS, MY, and FBMY groups showed a significantly increased mean seminiferous tubule area (p < 0.05), mice in the FB and MY groups had significantly higher sperm concentrations (p < 0.05), and mice in the EPS, FB, and FBMY groups showed significantly increased ratios of motile sperm (p < 0.05). Meanwhile, EPS significantly promoted the ability of JM mice to synthesize testosterone (p < 0.05). Furthermore, all CM products significantly increased the food intake of JM mice (p < 0.05) but did not significantly change their water intake and body weight gain (p > 0.05). In conclusion, CM products, especially EPS, exhibit strong androgen-like activities that can promote male reproductive development.

The association between serum estradiol levels and sperm DNA integrity

In men from the general population, BMI has been associated with a lower sperm DNA fragmentation index (DFI). We wondered whether this could be due to estradiol, which is associated with BMI and reported important for sperm function. Our objective was to investigate the association between estradiol and DFI. In 2008-2010, we recruited 284 young men from the general population to deliver samples of semen and blood and answer questionnaires. Serum concentrations of reproductive hormones and DFI were analyzed, the latter using the Sperm Chromatin Structure Assay. Associations were studied using general linear models. The first model utilized metric values of estradiol, whereas the second model compared men with high and low levels, dichotomized by the median value. A possible interaction between estradiol and testosterone was also examined. When investigating metric estradiol levels and DFI, an inverse association was seen without adjustments (p = .02), but the statistical significance was lost at adjustments for potential confounders (p = .08). Men with lower estradiol levels (<88 pmol/L, mean 71 pmol/L) had a statistically significantly higher DFI than men with higher levels of estradiol (≥88 pmol/L, mean 110 pmol/L). Mean ratio difference was 1.21 (p = .002) without adjustments and 1.18 (p = .01) with adjustments. A statistically significant difference in DFI was observed in men with testosterone levels below median when comparing high and low estradiol (p < .001). This study supports the idea that serum estradiol levels are protective for sperm DNA integrity, at least at lower testosterone levels.

Lipid Signaling During Gamete Maturation

Cell lipids are differentially distributed in distinct organelles and within the leaflets of the bilayer. They can further form laterally defined sub-domains within membranes with important signaling functions. This molecular and spatial complexity offers optimal platforms for signaling with the associated challenge of dissecting these pathways especially that lipid metabolism tends to be highly interconnected. Lipid signaling has historically been implicated in gamete function, however the detailed signaling pathways involved remain obscure. In this review we focus on oocyte and sperm maturation in an effort to consolidate current knowledge of the role of lipid signaling and set the stage for future directions.

Oxidative Stress in Men with Obesity, Metabolic Syndrome and Type 2 Diabetes Mellitus: Mechanisms and Management of Reproductive Dysfunction

Reactive oxygen species (ROS) are critical physiological mediators of cellular function, including male fertility. When ROS exceed antioxidant regulation, oxidative stress occurs which is detrimental to cellular function. Oxidative stress has been found to be a central mediator of obesity, metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM), as well as with male infertility. Human studies have correlated testicular oxidative stress in obese males, and animal studies have further provided insight into potential mechanisms of action. Management of oxidative stress is not well defined. Appropriate nutrition and exercise can be recommended for all diabetic patients, and weight loss for obese patients with MetS and T2DM. Consideration of dietary supplements including micronutrients, antioxidants or medicinal herbs are recommended. Metformin may also offer benefits on testicular oxidative stress and fertility parameters. Significantly more research on causation, mechanisms, clinical assessments and appropriate management of infertility on obesity, MetS and T2DM is still required.

Hua-Tan-Sheng-Jing Decoction Treats Obesity With Oligoasthenozoospermia by Up-Regulating the PI3K-AKT and Down-Regulating the JNK MAPK Signaling Pathways: At the Crossroad of Obesity and Oligoasthenozoospermia

Background: Oligoasthenozoospermia is the leading cause of male infertility, seriously affecting men's health and increasing the societal medical burden. In recent years, obesity-related oligoasthenozoospermia has attracted increased attention from researchers to find a cure. This study aimed to evaluate the efficacy of Hua-Tan-Sheng-Jing decoction (HTSJD) in treating obesity with oligoasthenozoospermia, determine its active ingredients and identify its mechanism of action. Methods: The ingredients of HTSJD were determined by combining the ultra-performance liquid chromatography with mass spectrometry (UPLC-MS/MS) and systems pharmacology approach. The common pathogenesis of obesity and oligoasthenozoospermia and the potential mechanism of HTSJD against obesity with oligoasthenozoospermia were obtained through target fishing, network construction, and enrichment analyses. Further, molecular docking of the key ingredients with the upstream receptors of the key signaling pathways of the potential mechanism was used to predict their affinity. Finally, high-fat-induced obesity with oligoasthenozoospermia rat model was constructed to determine the effects of HTSJD on semen concentration, sperm motility, body weight, and serum lipid metabolism. The key proteins were validated by immunohistochemistry (IHC). Results: A total of 70 effective components and 847 potential targets of HTSJD (H targets) were identified, of which 743 were common targets related to obesity and oligoasthenozoospermia (O-O targets) mainly enriched in the pathways related to inflammation, oxidative stress and hormone regulation. Finally, 143 common targets (H-O-O targets) for HTSJD against obesity with oligoasthenozoospermia were obtained. Combining the hub genes and the results of Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of H-O-O targets, PI3K-AKT and MAPK signaling pathways were identified as the key pathways. Molecular docking results showed that Diosgenin, Kaempferol, Quercetin, Hederagenin, Isorhamnetin may act on the related pathways by docking EGFR, IGF1R and INSR. The animal-based in vivo experiments confirmed that HTSJD improves the sperm quality of high-fat diet-fed rats by reducing their body weight and blood lipid levels, influencing the PI3K-AKT and MAPK signaling pathways and altering the corresponding protein expressions. Conclusion: HTSJD treats obesity with oligoasthenozoospermia by up-regulating the PI3K-AKT signaling pathway and down-regulating the MAPK signaling pathway, which are at the crossroad of obesity and oligoasthenozoospermia.

Role of PPAR-γ in diabetes-induced testicular dysfunction, oxidative DNA damage and repair in leptin receptor-deficient obese type 2 diabetic mice

The testis expresses peroxisome proliferator-activated receptor-γ (PPAR-γ), but its involvement in regulating diabetes-induced testicular dysfunction and DNA damage repair is not known. Pioglitazone-induced activation of PPAR-γ for 12 weeks in db/db obese diabetic mice increases bodyweights and reduces blood glucose levels, but PPAR-γ inhibition by 2-chloro-5-nitro-N-phenylbenzamide does not alter these parameters; instead, improves testis and epididymis weights and sperm count. Neither activation nor inhibition of PPAR-γ normalizes the diabetes-induced seminiferous epithelial degeneration. The PPAR-γ activation normalizes testicular lipid peroxidation, but its inhibition reduces lipid peroxidation and oxidative DNA damage (8-oxo-dG) in diabetic mice. As a response to diabetes-induced oxidative DNA damage, the base-excision repair (BER) mechanism proteins- 8-oxoguanine DNA glycosylases (OGG1/2) and X-ray repair cross-complementing protein-1 (XRCC1) increase, whereas the redox-factor-1 (REF1), DNA polymerase (pol) δ and poly (ADP-ribose) polymerase-1 (PARP1) show a tendency to increase suggesting an attempt to repair the oxidative DNA damage. The PPAR-γ stimulation inhibits OGG2, DNA pol δ, and XRCC1 in diabetic mice testes, but PPAR-γ inhibition reduces oxidative DNA damage and normalizes BER protein levels. In conclusion, type 2 diabetes negatively affects testicular structure and function and increases oxidative DNA damage and BER protein levels due to increased DNA damage. The PPAR-γ modulation does not significantly affect the structural changes in the testis. The PPAR-γ stimulation aggravates diabetes-induced effects on testis, including oxidative DNA damage and BER proteins, but PPAR-γ inhibition marginally recovers these diabetic effects indicating the involvement of the receptor in the reproductive effects of diabetes.